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Port 2400 (opequus-server)

IANA assigns port 2400 to opequus-server: OpEquus Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
opequus-server TCP OpEquus Server Gavin Hutchinson 2 -
opequus-server UDP OpEquus Server Gavin Hutchinson 2 -

Check what is listening on port 2400

Linux: is anything listening on TCP 2400?
sudo ss -tlnp 'sport = :2400'
Linux: UDP 2400
sudo ss -ulnp 'sport = :2400'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2400
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2400 '
Windows (Command Prompt)
netstat -ano | findstr :2400
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2400 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2400
From Windows
Test-NetConnection HOST -Port 2400
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2400

Block port 2400 in the firewall

ufw
sudo ufw deny 2400/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2400 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2400 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2400' -Direction Inbound -Protocol TCP -LocalPort 2400 -Action Block
ufw
sudo ufw deny 2400/udp
iptables
sudo iptables -A INPUT -p udp --dport 2400 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2400 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2400' -Direction Inbound -Protocol UDP -LocalPort 2400 -Action Block

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All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.